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Thread: Fast Fred's Secrets of the OMC MOD50's Thread #1

  1. #421
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    anywho, at test done at the factory on the 56er, with, without modded exhaust, long rods, 2bbls, it never made more than 102hp no mater what.

    in tests done by my number one tester, at 800ft it's all 56er, low end torque is better.....

    ? don't know whats to tell yas on the 2BBLS, thare are two kinds, first kind is Mod50 carbs the other kind is all the rest, mod 50 has a specific main nozzel,
    with out the nozzel the moda will just wash out with fuel.

    my carbs took a lot to work out, the hull Leaves out in like 5ft, on plain and pullin as hard or harder than any Ruba boat i've ever seen

  2. #422
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    i gots a Mod50 with press in liners, has the 56er exhaust port, she needs new sleeves, think that would be some thing you could do
    Bill Gohr

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    Team Member Sam La Banco's Avatar
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    Hey Detroit Whitey, I used the stock reed cages, I added one more openning in them, there is enough room on one side. Made a fixture to hold the blocks and machined the holes. Modified the crankcase opennings a bit.

    The whole idea was to get a better (modern) carb on the motor, one that could be "tunned" better than the stock carbs, which are very crude compared to newer designs. I knew the motor could not deal with a lot more fuel.

    I think the guy's are trying to run the water backward because they found that was how we set it up in the SST 45 motor when we were developing it. It ran better running that way, but that doesn't mean all motors will, don't know about the 49 cuber. As far as I know it doesn't have any cooling problems that I know of. Will it run better with the water running backwards, only testing will tell.

  4. #424
    Team Member Bill Gohr's Avatar
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    Default BVackwards cooling

    Quote Originally Posted by Sam La Banco View Post
    Hey Detroit Whitey, I used the stock reed cages, I added one more openning in them, there is enough room on one side. Made a fixture to hold the blocks and machined the holes. Modified the crankcase opennings a bit.

    The whole idea was to get a better (modern) carb on the motor, one that could be "tunned" better than the stock carbs, which are very crude compared to newer designs. I knew the motor could not deal with a lot more fuel.

    I think the guy's are trying to run the water backward because they found that was how we set it up in the SST 45 motor when we were developing it. It ran better running that way, but that doesn't mean all motors will, don't know about the 49 cuber. As far as I know it doesn't have any cooling problems that I know of. Will it run better with the water running backwards, only testing will tell.
    Thats the way it was always done on race engines, starting with the KC13.

    And I agree with Sam, those motors have plenty of reed area with just some modifacations, we made mod 50 stuff with 4,5, and 6 petal assemblies which never really helped anything, maybe made some peak power over 9K but didn't help anything else.

    As far as the carbs go, you need to buy Sam's adaptors and fit some 42mm BN's to it. The one barrel set up came out in what 1968 with minor changes, of course a different carb would be better.

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    had me some of them Mikuni fed 3cyls 2 strokers. after many tests it is my opinion that the 56er is geometrically challenged, and is not capable of the peak
    hp of the 49,i've heard tails of dynoed 56ers hittin 115hp. we can see in ads
    for SST60 power heads with dyno slips, a nice one is about 100hp , finger ports
    would , could make about 12-15hp. some slide bores could be nice

  6. #426
    John (Taylor) Gabrowski
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    Default Carb inlets of the 49 inch 3 Holers and other stuff I find weird?

    Being new to the 49 inch OMC 3 Holers having bought a new NOS complete block and all the parts from its blown up predessor fishing engine, looking at carb inlets sure has me puzzled. Like why are these casting obstructions that change direction in the carb base flow are so abrupt? It would seem something could really be improved upon there to make tunning better? Have any improvements been made in this area to improve air/fuel streaming or was it all very good to begin with even with these kinks? Or is this forbidden territory rules wise?

    I have set Mercury Twister racing sled reed boxes from a 440 that in effect are in front of the piston port where these sleds used 1 Tillotson HD per cylinder. The reed boxes must have been installed to inprove on midrange power that would have been installed because of piston port spit back problems. Even these reed boxes have a split bar immediately under the carb dividing the air/fuel stream in 2 to saturate both sides of the reed box before going into another HD carb sized inlet port facing the piston port. All this air/fuel stream splitting and changing air/fuel direction must ultimately affect overall power negatively would it not. I am actually thinking of bolting a Mercury reed box like these on to an Anzani and then bolting the Vacturi on top of it because that engine has tremendous spit back at low to mid range high side rpms where the motor finally catches up and does not let the spit back come out of the engine anymore.

    What are your thoughts?

  7. #427
    Team JDS Jeff Akers's Avatar
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    Quote Originally Posted by formeone View Post
    just food for thought and i didnt read all the reply's but all you talking about bigger carbs????... i own the kilo in class ..and i used the 55hp carbs????...go fig,,,maybe just set up?? or lots luck????...

    Hey , Cheyney good to see you snoopin around on the net again, you planing a comeback soon ?

    The engine that Fred is playing with is using the shifter gear case and on much bigger boats than what you and I drive. and the rules are different allowing more mod's to the intake and carbs. some of the info doe's however cross over to Formula E. Definitely some great info for those wanting to get the most out of an OMC 3 holer ! .... Oh, FYI:...... I use the small bore carbs on my engines too.
    Jeff 93-C



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    jeff,,, will be back raceing this comming summer,, liveing in spokane now,,, soo hopefully can get going above 100mph again,,,we shall see,,,

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  10. #430
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    ok, this is the port map

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